Posted
by
timothy
on Saturday April 10, 2010 @07:59PM
from the will-stick-with-the-regular-kind-for-now dept.

separsons writes "Scientists at the University of South Carolina recently transformed ordinary T-shirts into bulletproof armor. By splicing cotton with boron, the third hardest material on the planet, scientists created a shirt that was super elastic but also strong enough to deflect bullets. Xiaodong Li, lead researcher on the project, says the same tech may eventually be used to create lightweight, fuel-efficient cars and aircrafts."

Actually the elasticity of these things change with the among of force applied. When you try to punch these things hard (just like a bullet does) they seem to rigid. But when you try to handle them with less force, like try to slowly pull or push them (just like when you try to wear them), they seem to be really elastic.

So your question should be rephrased as how elastic it is, when a bullet strikes it? Is is strong enough to distribute the force of the bullet through out your torso and not cause a serious dent?

Actually the elasticity of these things change with the among of force applied. When you try to punch these things hard (just like a bullet does) they seem to rigid. But when you try to handle them with less force, like try to slowly pull or push them (just like when you try to wear them), they seem to be really elastic.

Actually the elasticity of these things change with the among of force applied. When you try to punch these things hard (just like a bullet does) they seem to rigid. But when you try to handle them with less force, like try to slowly pull or push them (just like when you try to wear them), they seem to be really elastic.

So your question should be rephrased as how elastic it is, when a bullet strikes it? Is is strong enough to distribute the force of the bullet through out your torso and not cause a serious dent?

The force applied to the target by a bullet is less than or equal to the force applied to the hand or shoulder of the shooter. If it didn't knock the shooter over, it probably won't knock you over, if the force is spread over a larger area. Newton's laws still apply...

You forget one thing, though. Shooters are generally standing in a very stable stance exactly for the reason not being knocked down. Try a less stable stance and the recoil might just knock you off your feet.

The energy applied to the target by a bullet is less than or roughly equal to the energy applied to the gun, flesh, other springy elements in between the bullet and hand or shoulder of the shooter.

FTFY. It's a small textual change, but has huge implications in terms of terminal ballistics. What you can easily absorb as the shooter is pretty significantly different than what you can absorb as impact on your flesh from the bullet side. Believe me, you can kill someone with the blunt force trauma that dissi

The dE/dT applies quite strongly here, the dE/dT is much lower for the shooter because the dT is longer as the projectile is accelerated through the barrel, at the other end the bullet either is stopped with a very short dT or it penetrates. The material in the article would be very useful in a layered approach; such as worn as a tee shirt with more conventional body armor providing the majority of protection.

This would have more uses then just people getting shot at. Anyone who may take a blow from something could benefit. Like construction workers, police, perhaps animal handlers, motorcyclists.. If they make gloves there would be even more uses.

Ye old flak vests had metal. However, in my experience, no modern vests have metal plates at all. If a vest has a metal component, it is usually kept in a pouch *on the front* of the vest, where a bullet simply passes through, to be absorbed by the kevlar/aramid/textile component--offering virtually no benefit against bullets or their blunt trauma.

What it does, however, is give protection against stabbing and puncture weapons, which traditional vests alone do not protect against. Even then, the metal insert

You must be a cop;) not sure if you were deliberately leaving ceramic plates out of the discussion, so I'll bring up the differences a tad

Vests can have metal or ceramic plates, or they can be made entirely of something like kevlar. Global security has a pretty good List of Body Armor Classes [globalsecurity.org] that explains them.

Plates are almost always removable because that just makes the most sense in so many damned ways (as I'm sure you know). Here's a cheap-o type III with optional removable steel plates: GatorHawk T [afmo.com]

That would be great if true but the reality is that steel plates are added because Kevlar only prevents penetration of low cal projectiles. If you add the plates (which aren't always steel) you can increase the rating to include some armor piercing shells and higher cal ammo.

I think "bulletproof t-shirts" is just a bit of verbal hyperbole from the reporter, albeit fitting in regards to the process that led to the creation of this material.

The main breakthrough of the process is that the third strongest material in the world, which was previously only accessible in a ceramic (read: brittle and crystalline) form can now be formed around templates of carbon fibers (the aforementioned, t-shirts baked to perfection).

In other articles, the main emphasis is definitely on this new stronger material being an improvement on current ballistic fibers such as Kevlar.

Nah, it would only increase the use of force. "The tazer didn't work, so we shot him in the head."

Bullet proof vests are only good if the bullet his your chest. It doesn't help in other areas.

In reality, "bullet proof" materials are only good at spreading the energy out. They're worthless against more focused forces. It may stop a 9mm (blunt tip), but it won't stop a.223 (sharp tip), and probably won't do much against the electrodes of a tazer, or a knife. That's why they make rifle plating to go into kevlar vests. They're heavy, but they'll help protect against more serious rounds. With serious rounds (like a.50 BMG), you can't carry enough armor to help you, and even if you did, it can only displace the energy so far. If it was able to prevent the round from piercing the armor, you'd simply be crushed by the force.

Best advice for not getting killed by bullets? Don't get yourself on the wrong end of a firearm. I've managed to be safe wearing regular t-shirts as protection for over 30 years, because I've never put myself in the way of a weapon.:)

I've managed to be safe wearing regular t-shirts as protection for over 30 years, because I've never put myself in the way of a weapon.

This may hold more weight if you elaborated on your line of work or hobbies. If nothing in your ordinary routine involves firearms then I could claim this also.

I'm a 26 year old student studying graphic design and multimedia development with no real hobbies outside video gaming. Other than shooting hares with an air rifle on Dad's farm I've had little contact with real firearms, and I've manage to be safe wearing regular t-shirts as protection for almost 30 years!

And I think skaet's point was that staying safe by not getting shot at isn't applicable to everyone's line of work. I.e. The GP saying "just stay out of the way" isn't going to help a soldier or a police officer much.

I don't know what a.50 BMG is, but I'm guessing it has to be shot from a Tank or Howitzer -- because if a person shot it, then the only amount of crushing you have to experience is the amount they did when they shot you.

.50 is the caliber of the round, 12.7mm or half an inch.BMG stands for Browning Machine Gun [wikipedia.org], which is what the ammo was once designed for.

As for serious rounds, there's actual handguns [wikipedia.org] out there that fire.50 cal rounds [wikipedia.org], so no need for a tank or howitzer.

That would be a HUGE seller for demonstrations, students in libraries, passengers at airports, etc.

I could see some airtravelers buying it not realizing that if a terrorist did attack, he wouldn't be shooting them. Demonstrators usually are facing clubs and gas, but I guess some might be interested there too.

What kind of students and what kind of libraries though are you thinking of?!?

Elasticity is actually the important bit - the energy of impact goes into deforming the material instead of just being transmitted to what is underneath.Remember that it doesn't have to be thin and skin tight. Just being lighter than a big pile of Kevlar is a huge bonus. Some sort of padding or layers of air just to give the stuff room to deform before it hits skin and bone should work.

This is Slashdot you're writing on. The median group here can sustain a 2 inch penetration and barely bleed. It'll only bruise their fat.

The question is, what kind of force can it take? I know body armor is rated for various forces. Not much is going to stop a 50cal BMG, but I'm sure it would do a good job on a.22 shot from 100 feet. Then again, a cheap leather jacket would do the same thing.:)

Actually, 22LR is a rather potent round! Penetration beyond 13" [brassfetcher.com] is possible with 22LR in an 86mm long barreled pistol. Denim and leather jackets add little in terms of protection, but even level II will easily stop the 22LR.

.
Yes, one of my jobs is related to design and sourcing of bulletproof clothing, typically from Chinese factories for South American clients. I get to shoot gelatin, mannequins and all sorts of things for a part of my living!

Penetration obviously isn't ideal, but having the bullet contained by the shirt would still be a preferable outcome to outright penetration. One of the reasons the Mongols wore silk armor was that when struck by an arrow, the arrow would often fail to pierce the silk. This made removing arrows much easier and cleaner, which meant less downtime for wounded fighters.

It isn't going to help much if the bullet has enough force to make the t-shirt penetrate you. If we're talking a 2-inch stretch, then it'll make things less messy, but no less lethal.

Actually, this is exactly why most people who are shot while wearing modern vests typically have broken ribs and/or other bones. There are only a small number of ways to effectively and pragmatically stop a bullet. One is to deflect it like an armored vehicle. The second is to completely absorb the energy by means of a sacrificial material, such as ceramics. These materials are typically only good for stopping a bullet or two. The third is to prevent penetration and to slow the round as quickly as possible

Actually it is likely to be worse because instead of the bullet penetrating through (which happens most of the time) all the kinetic energy will be dumped into you and the shockwave will probably shatter blood vessels and organs anyway. Pistol rounds don't normally shatter, and rifle rounds have way too much KE for this to be a good idea.

How does an "advancement" [popsci.com] turn into a "finished product"?

From the (5 day old) pop-sci article:

Outside experts have deemed the approach promising, if not yet ready to replace Kevlar or conventional bulletproof materials. But the boron-carbide nanowires already show some material improvement over more brittle boron-carbide composites.

Even if a super tough but flexible fabric were made, then they would still have to make it rigid upon impact.

The Huns wore silk to protect themselves in battle. There were no bullets back then, just arrows and blades. While the arrows could still penetrate the flesh, they often did not cut through the silk which made it easier to remove the arrows and stem the bleeding. BTW, like tee-shirts, silk is imprintable -- "We're on the run, we're lotta fun, we are the Huns!"

The Huns wore silk to protect themselves in battle. There were no bullets back then, just arrows and blades. While the arrows could still penetrate the flesh, they often did not cut through the silk which made it easier to remove the arrows and stem the bleeding. BTW, like tee-shirts, silk is imprintable -- "We're on the run, we're lotta fun, we are the Huns!"

Yes, that's actually true! They also wore silk scarves to prevent neck chops, because "there can be only Huns!"

Does this mean you could construct Batman's body armor in reality? A full-body flexible armor suit like one of those cow-hide things some motorcyclists wear? That would be nice, to say the least. At the moment you're limited to aramid-weave clothing, this takes knives but doesn't stop bullets or blunt force.

Ugh the writers of the article (and, consequently, the slashdot user) wrote a badly worded description. I was surprised as I never heard of any particularly strong allotrope of boron. If you actually read the whole thing, it's boron nanowires that give the strength. Key word: nanowires. Researchers used boron, but there are plenty of different materials to make nanowires out of. And it is the particular properties resulting from reinforcing materials with nanowires that give the 'bulletproof' strength.

I think there's a good deal of misunderstaning about bullet resistant soft body armour on here. I've seen two posts so far that say that the shape of the bullet has something to do with defeating a vest, as well as a bullet being "tangled up" by the material. Neither is true.

Bullet resistant soft armour works because of the strength of the individual fibre and how its woven. It also has to do with the friction coefficicent of each fiber. Generally, it's woven in a waffle or checkerboard pattern for each layer. There are lots of layers, too...20 or 30 is common. When a projectile strikes the fabric, the crossed fibers lock against each other (this is where the friction coefficient comes in. Two Kevlar fibers crossed at 90 degrees will not want to move). So, in theory, one layer could stop a low-energy bullet. However, it would still be fatal to the person wearing it because of the amount of energy transferred to them. So, by using multiple layers, that.38 or 9mm round's energy is spread out over perhaps 5 or 6 inches. It's still going to hurt like hell, but you'll live to tell the tale. Current NIJ spec for the backface deformation of a vest is something like 12" of clay, which translates to something like 4 or 5 inches of compression in a human. It's like getting hit with a baseball bat swung by a AAA player.

So why does bullet shape have little to do with it? Even a pointed bullet deforms on impact; the sharp point isn't going to get through more than a layer or two before it deforms flat. The threat rifle rounds offer is that there is just vastly more energy then a pistol round. All of these materials have a failing point, and even if the bullet was stopped, the amount of energy transferred to the wearer might be lethal anyway.
That's why rifle-rated vests (something to stop a.223 or a 30-06) have trauma plates, which is a 1/4 inch (or thicker) ceramic plate. It's heavy, uncomfortable and unbendable, but it'll stop just about any reasonable threat.

Sure, we could come up with a list of unreasonable threats, but in reality most shootings are with lower energy handgun calibers (9mm/38spl/25acp/32acp), which a standard IIA vest will stop without breaking a sweat.

If it stops a 9mm shell, it'll stop the little barbed prongs that a taser shoots. But they might catch in the clothing anyway, so you might still get shocked. Unless this stuff is conductive enough to short it out, or insulating enough to protect you.

No, it doesn't work that way. A "bulletproof" vest is relatively easy to get through with a sharp blade - most bullet resistant materials will use lots of strong fibres to tangle the bullet up in on it's way through, whereas a sharp knife (or a pointed barb that's not spinning) will penetrate relatively easily.

If it stops a 9mm shell, it'll stop the little barbed prongs that a taser shoots. But they might catch in the clothing anyway, so you might still get shocked. Unless this stuff is conductive enough to short it out, or insulating enough to protect you.

No, it doesn't work that way. A "bulletproof" vest is relatively easy to get through with a sharp blade - most bullet resistant materials will use lots of strong fibres to tangle the bullet up in on it's way through, whereas a sharp knife (or a pointed barb that's not spinning) will penetrate relatively easily.

Ok, but in the future, just say "The slow blade penetrates the shield."

Nearly any level II, III, or IIIA bulletproof vest on the market today is also blade resistant; you need an icepick to get through them, but any blade with any height (more than 10mm wide) will pretty much be stopped. And all are thicker than the length length of the taser barb (right around 10mm), and will stop the low velocity and low force of the barb without a problem.

Depends on the armor. The armor that I wore in Iraq had (I'm pretty sure it was made out of this) boron carbide plates in it. Also had a mesh to resist cracking so you could be shot more than once while wearing it. The plates were not all over the armor, however they were pretty large and covered a good portion of the body. Of course all this had the penalty of being pretty heavy, add weapons and ammunition to the kit and your in the 20lb+ range.

No, it isn't [wikipedia.org]Elemental boron and borates are non-toxic to humans and animals (approximately similar to table salt). The LD50 (dose at which there is 50% mortality) for animals is about 6 g per kg of body weight. Substances with LD50 above 2 g are considered non-toxic.